A $5 billion deal is about to make ConAgra the largest supplier of stores’ own-label foods in America.

The food industry giant said that it had maintained its pursuit of Ralcorp, despite several rejections, because of the irresistible allure of a booming market for so-called private labels.

Sales of such goods have been growing about twice as quickly as those of branded products over the past 13 years and the pace has picked up still further during the downturn. They now account for 18 per cent of the overall packaged food market.